Alternating-current telegraph and telephone duplex.



.l. P. FERRITER.

ALTERNATING. CURRENT TELEGRAPH AND TELEPHONE DUPLEX. APPLICATION FILED sEPT'. 20. 1916.

1,251,208. Patented Dec. 25, 1917. 2 SHEETS-SHEET n.

II II I ll wlmssis INVENTOR Z4 gzoyze c/fifk/raz'lf J. P. FERRITER. ALTERNAHNG CURRENT TELEGRAPH AND TELEPHONE DUPLEX.

'APPLICATION FILED SEPT. 20, I916.

Patented Dec! 25, 1917.

2 SHEETS-SHEET 2- y NYE/IrondEF/fli/ WITNESSES A "OBI/E78 JOHN, PATRICK rnnarrnnj-ior, JACKSONVILLE, FLORIDA; ,ASSIGNOR on ONE-HALF T0 'rHoMAs J. PETERS, or; r 'TERs, FLORIDA. I

amnnnnrino oimnnnr f'rntnenArn A r-n ,TEL PHon LnUPLEx.

If re i e ti' of t r iP I-wn Patented D.ec. 25,'1917.-

Application filed September 20,1916. SerieLlNo. 121,144.

To all whom it'may concern:

Be itwknown that I, JOHNP. 'FERRITER, a citizen of the United States, and a residentof Jacksonville, in the county of Duval and State of. Florida,have invented a new and. Improved Alternating- Current: Telegraph and Telephone-Duplex, of which ithe following is a full, clear, andiexactddescription.

This invention relates to telegraph and telephone rsystems, and has for cits-general object toiprovide a-novel, reliable and eflicient alternating current telegraph and telephone duplex which is adapted i to operate on-wires already inuse, such-1:as telephone circuits ordirecticurrent, singleovmultiplex telegraph circuits, 'or on 'a=circuit'. used for no otherservice;

v A more specific object ri t he provision of a junction coillof special Construction, espe- :cially adapted for duplex =workiwith a high frequency alternating current; 7

Still: another object of theiinvention is to provide anove'l combination ofjunction coi-l for an alternating current telegraph and telephoneduplex system with a source of high frequency alternating current, a telephone transmitter and telephone receiver and appropriate circuit connections, whereby -the junctionucoil can be connected 'with single or double wire circuits'for telegraph or other service, or with single. or. double wire. circuits limited toiuse with the duplex.

With; such objects in view, and others which will appear as the description-pr0- ceeds, the invention comprises various novel features of construction and arrangements of parts which' will be. setforth with particularity in the following descriptionand claims appended :hereto.

In the accompanying; drawings, which illustrate certain embodiments of the invention and wherein similar characters of reference indicate corresponding parts in all the views, i I v Figure 1 is a diagrammatic view of-the in vention coupled to a direct current single or multiplex telegraph circuit;

Fig. 2 is a' diagrammatic view-showing the duplex coil connected with a metallic telephone circuit;

Fig. 3 is a diagrammatic view showing the: duplex connected to a metallic tWQ-WIIG c1r-.

cuit utilized for no other service;

Figs. 4, 5 and 6 are diagrammatic. views showing dlfferent arrangements in .WhlCll the,

duplex-is connected with the circuits through repeating coils;

Fig; a. diagrammaticview showing the manner of modifying the instruments aean intermediate station when thevduplex is usedi infa telegraphcircuitgiand ,Fig; 8 is a fragmentary View showing: diagrammatically the primary of the junc' tion coil; v j i Referring to the drawings, ,=A designates means for generating, highfrequency alter nating current, B the-junctioncoil and: thell-i-ne wire. The source of-high frequency; alternating currentmay be an induction coil,: Poulsen are or thelike,but in the presentiin-w 'stance aa-buzzer transmitter, which consti-,- tutes the, subjectmatter of my; co-pendin'gj application, Serial l T;uInber-121A22,-v is'shown. This; buzzer transmitterwconsists of a long; core 1 having-wound thereon, a l0w-resistance winding 2, and both-:thecwinding and corearezinclosed ina meta-litube 3.v Atrone end of -thecore, is a make-and-break device in the formofa resilient contact 4 carrying an armature 5 andzan adjustable contactG, the contacts being connected iniseries with. the winding-,2, aikey and a battery 8, which latter is connected alsoywith thewinding ;-2.; A telephone transmitter 9 is dis posed attheend of the? core 1 opposite. from the interrupter, ,andincludesan armature 10 which vibrates in harmony with the mag; netic fluxes set up by the winding as the current-is. made andbroken. The telephone, transmitter "9 is connected ina primary cir--- cuit which includes a battery 11 and a wind ing112g-of an induction coil 13. The/sec ondary 14 of the induction coil has'one ter-;

minalconnected to ground at 15-and the other terminal connected at 16 with the junction coil. 1

The buzzer transmitter constructed as de-' induced currents typical'inbuzzer transmit- K ters. This absenceof brush currents makes it possible'to operate the-.herein-described du plexwithout materially interfering inductively with similar circuits or telephone circuits on adjacent wires, whlch hasheretofore been impossible. a

The junction coil 13, which-constitutes the dicated by the dotted lines, Fig.'*'1,--and' wound around this core .are two primary windings 18 and 19 formed of twisted wires hehcally colled, whereby current passing through the wire simultaneously will setup no magnetic actlon 1n the core, provided thew windings are balanced. The secondary 20 may be a single Wire. or a twisted pairof wires, and this secondary is inductivelyrelated to the primary windings by being coiled around'the latter, although this relation is not shown in Fig. 1.- The terminals of the secondary winding are connected with a' telephone receiver 1".-- One terminal of the winding 18 i connected by a wire 21 with the binding post 16, and the opposite termi nal of the winding 19 is connected by a wire '22 with -the-ssame binding post 16.

The other or free terminal of the primary 18 is connected through a condenser 23 witha line wire C, while the'free terminal of the winding 19 is connected to a condenser 2 1' with a variable resistance or rheostat D.- The-adjustable terminal 24L of thisre'sist ance D is connected to ground at 25. In'termediate points'26 and 270i the resistance are connected through condensers 28 and'29 with the ground'at 30.

The use of a'condenser-between the junction coil and the line'is forthe purpose of avoiding interference of a direct current circuit on the same wire, and'the condenser between the unction c011 and the rheostat is to balance he capacity'of the first-mem' tioned condenser.

By reason of the specially constructed junction coil an outgoing current sets up no magnetic action in the core,and consequently sets up no current in the secondary winding which is connected with the receiver, assuming the'duplex to be balanced. This type of junction coil is essential in alternating cur rent duplex, as otherwise it takes verylittle unbalance in a coil to cause interference by thehome signals. I

To operate the device as a telephoneduplex, no change in the layout is required, as the telephone transmitter adjacent to the buzzer transmitter and suitably connected with the transformer 13 is available for talk ing as well as for telegraphing. If desired,

however, a separate talking transmitter can be provided for telephoning by using a switching arrangement.

lVhen operating on a wire already in use as a direct current single or multiplex telegraph circuit, a retardation coil 31 is placed in the line between the direct current instruments and the point where the alternating current set attaches to the line. The terminal of this retardation coil nearest the direct current set'is connected to the earth at 32 through a condenser 33 of about one microfarad capacity. This arrangement fiattens out the direct current impulses and prevents direct current interference in the alternating current receiver. The retardation coil also prevents any of the alternating current reaching the direct current instruments;

When the alternating current duplex is used on lines already carrying a direct current single circuit with various offices on the line, it is necessary, as shown in Fig. 7, to bridge the instruments at each intermediate office with a condenser 34, and a small resistance 35 is placed in series with the direct current instruments, such as the relay 36 and key 37. The condenser provides a path for the alternating current whether the key is open or closed. The resistance regulates the discharge of the condenser in such a manner as to materially assist the direct current relays operation.

Fig. 2 illustratesa method of connecting the. alternating current duplex to a metallic telephone circuit, without interfering :withsaid telephone circuit.- -38 and 89 are each one microfarad condensers, one-terminalof:

each being connected with a telephonev wire. The other terminals, of the-two condensers are connected to the alternating current dupleX or junction coil. r

Fig. 3 illustrates amethod of connecting the duplex. to twowires .410 andal which are not in other service. be used to advantage where a telegraph or telephoneduplex is required on a long circuit and a pair of transposed wires are available, as,.wh'en transposed wires are ,used, no provision has to be made to overcome'the effect of line noise.

Any desired number of alternating current duplexoifices maybe installed on a circuit, whether the line is in direct current use or not.

Figs. 4-, 5 and 6 show a different arrange ment of the alternating current instruments.

nals of the secondary winding 46 on the second repeating coil are connected with the terminals of a variable resistance 47, portlons of which lGSlStElllCGhELVG condensers 4L8 paralleling them. These are the balancing resistance and condensers. One terminal of the secondary winding .49 .on the first re- This method can peating coil is connected to the line through a condenser 50, as in Fig. 4. The o'ther terminal is connected to the earth at 51. One terminal of'the talking coil secondary 14; is connected to the junction coil primaries. The other terminal is connected at 52 to the twowindingsAtSj and l of the repeating coils E and F. In Fig. 5 the sec ondary winding of the repeating coil E has its terminals connected to the two 'wires 40 and "ll" ofa circuit used for'noother service; andin Fig. 6 the secondary winding has one terminaljcjonnected with the telephone line wires through condensers 38 and 39, and. the other terminal connected to ground.

The advantage in a duplex arrangement for a telephone circuit s that, on account of the absence ofinterference fromhome sig nals in the receiver, a carbon transmitter repeatercan be used effectively. Heretofore, 'such a repeater could not be used to advantage by reason of the howling the repeater transmittersset up after being in use a few minutes. This trouble does not occur when a telephone duplex is used.

Having thus described my invention, I

claim as new and desire to secure by Letters Patent:

1. In a system of the class described, the combination of a source of high frequency current, a junction coil having a primary formed of twisted wires helically wound, one end of one wire and the opposite end of the other wire being connected together, an induction coil between the said source and the connected ends of the junction coil primary, a line wire circuit, condenser means between the line wire circuit and one of the wires'of the primary, a variable resistance having a grounded terminal, and a condenser between the other terminal of the variable resistance and the other wire (j the primary.

2. In a system of the class described, the combination of a source of high frequency current, a junction coil having a primary formed of twisted wires helically wound, one end of one wire and the opposite end of the other wire being connected together, an induction coil between the said source and the connected ends of the junction coil primary, a line wire circuit, condenser means between the line wire circuit and one of the wires of the primary, a variable resistance having a grounded terminal, a condenser between the other terminal of the variable resistance and the other wire of the primary, and a receiver connected with the secondary side of the junction coil.

3. In a system of the class described, the combination of a source of high frequency current, a junction coil having a primary formed of twisted wires helically wound, one end of one wire and the opposite end densersconnected with intermediate points of thefvariable resistance and connected with the grounded terminal of the variable resistance.

4t. In a system of the class described, the

combination of a source of high frequency alternatingcurrent, an induction coil having a winding connected with the. said,

source; and another winding provided with a, grounded term nal, a unction coil including twisted wireshelicallyfwound, each con-,

nected with jtheungrounded terminal of the second-mentioned winding formingfa primary winding and a secondary winding inductively relatedithereto, a receiver connected with the secondary winding, a line wire circuit connected with one of the said wires, a variable resistance connected with the other Wire, a pair of condensers connected with different portions of the variable resistance, and a connection between the condensers and the other terminal of the variable resistance.

5. In a system of the class described, a line wire including station instruments, a resistance in series with the instruments, a condenser bridging the instruments and resistance, a retarding coil in the line Wire, a grounded condenser connected with the line wire at the side thereof leading to the said station instruments, a junction coil connected with the line wire at the side of the retarding coil opposite from the grounded condenser, said junction coil having its primary formed of helically wound twisted wires, one end of one wire and the opposite end of the other wire being connected together, a condenser between one of the wires and the line wire, a condenser connected with the remaining end of the other wire, a secondary associated with the said primary winding, a receiver in circuit with the secondary, a variable resistance conmary Winding, means for generating high frequency current inductively connected with the connected ends of the Wires of the primary Winding of the junction coil and including a transmitter.

7.' In a system of the class described, the

combination of a junction coil having a sec ondary Winding and a primary Winding, said primary Winding being formed of a pair of twisted Wires helically Wound, a receiver connected With the secondary Winding, one end of one Wire and the opposite end of the other Wire being connected together, a line circuit connected With the primary Winding, an induction coil having its secondary connected with the connected wires of the junction coil, a transmitter in the primary circuit of the induction coil, and means for producing high. frequency (Joules this patent maybe obtained for current in the primary circuit oft he induction'coil, i I

8, In a system ofthe class described, the combination of a junction 'coil having a secondary Windingand a primary Winding, said primary winding being. formed of a pair of twisted Wires helically'wound, a receiver connected With the secondary Winding, one end of .one' Wire and the opposite end of the other Wire being connected together, a line circuit connected With the primary Winding, a buzzer transmitter, a controlling circuit therefor, means associated With the buzzer transmitter for eliminating brush currents, a telephone transmitter actuated by the buzzer transmitter, a source of continuous current connected With the telephone transmitter, and an in! duction coil having its primary in the telephone transmitter circuit and its secondary connected with the connected Wires of the junction coil. I

JOHN PATRICK FER I ER,

five cents each, by addressing the Commissioner of Patents. Washington, D G. 

